Crosbie was a housemate with Strood and Lynda on Big Brother when the Ninth Doctor was transported to. She was the eighth housemate to be evicted. A great cook, she apologised for stealing Lynda Moss's soap.
Although apparently disintegrated, she was actually transmatted to the Dalek mothership, (TV: Bad Wolf) where human captives were having their cells extracted and cultivated into a Dalek army by the Emperor. (TV: The Parting of the Ways)